Slingshot's hydrateQueryResponse batch proxy rejects requests that include an authorization field - it returns 400 whenever the field is present, regardless of whether the token is valid (verified live: identical request 400s with the field, succeeds without it). The earlier service-auth wiring therefore made every logged-in custom-feed batch fetch 400, which collapsed buildCustomFeed to an empty page on re-fetch. Revert to the logged-out-only batch path: logged-in users use the AppView, which forwards viewer auth correctly for personalized feeds. The batch path keeps its speed win for logged-out browsing.